Shred the sweet potatoes using a food processor. (see note below on doing this overnight)
Mix sweet potato shreds, eggs, chopped green onions, and salt in a large bowl.
Heat the avocado oil in a cast iron (or another high smoke point oil). You'll know it's hot when you flick water into the pan and it sizzles.
Pack a handful of the mixture (about 1/4 cup) in your hands and press into a patty. Place on the cast iron, and flatten slightly with a spatula. Add a few more latkes into the cast iron (mine fits about 4)
Let the latkes sizzle and crisp up for about 3 minutes. Flip and cook for another 3 minutes.
Remove from the cast iron and place on a plate with paper towels to allow for excess oil to drain.
Repeat with the rest of the sweet potato shreds. Since the oil is hot, the next few batches may cook up faster. Feel free to add more oil (and make sure it's hot) in between rounds.
Serve with sour cream or apple sauce!
Shred your sweet potatoes the night before, place in a sealed container with paper towels. This will help absorb the moisture, and make your latkes less soggy and crisp up better!